The concept of video communications is long known in the art, and is on the verge of becoming mainstream with the advent of UMTS mobile handsets, capable of transmitting and receiving video streams. An example of such a service publicly available in the UK is that of the “Three™” service offered by Hutchison 3G UK Ltd. Additionally, other video-conferencing services are also well-known in the art, such as those provided over the Internet using a software application such as Microsoft® Netmeeting® running on a general purpose computer system equipped with a camera and a network connection, or by using dedicated video-conferencing hardware.
It is common within video communications systems to provide a video image not only of the remote particpant(s) to the video conference or video call, but also of the local participant(s). Such visual feedback allows the local participant to see how the remote party sees them and to see how the video-conferencing system is representing them. Additionally the visual feedback also enables the user to position themselves within the camera's view and ensure their face is well lit and visible.
Several examples of visual feedback systems for video communications are known in the art, as are shown in FIGS. 1, and 2. More particularly, FIG. 1 illustrates a common arrangement for visual feedback wherein a display screen 1 is divided into a remote display portion 2, and a local display portion 3. The remote display portion 2 displays the incoming video signal received from the remote user (usually via a network of some form), whereas the local display portion 3 displays a video image of the local user as captured by the local terminal's image capturing means such as a camera or the like. Examples of such an arrangement known in the art are those used by both Hutchison 3G UK Ltd in the “Three” service, and by Microsoft Corp in the NetMeeting software application.
Alternative forms of visual feedback are also known in the art which do not divide the display screen 2 into portions, but which combine the local images and the remote images into a combined image, such that the remote user(s) and the local user(s) are displayed side by side on a common background. An example of such a system is the “Reflexion” system developed by Media Lab Europe, and described at http://www.medialabeurope.org/˜stefan/hc/projects/reflexion/. Several screen shots of the Reflexion system are shown in FIG. 2.
A Reflexion station consists of a camera and video display connected to a computer. Each participant, of which there can be several, uses a separate Reflexion station. Using a segmentation algorithm, the computer extracts an image of the participant from his background and transmits a mirror image of it over the network to the other stations. The computer also receives extracted participant images from the other stations and combines them all together into a single video scene. The effect is one of a “digital mirror” in which the participant sees a reflection of himself as well as the reflections of the other remotely-located participants.
The system automatically monitors auditory cues and uses them to compose the scene in a way that enhances the interaction. For example, the current prototype tracks which participants are speaking in order to judge who is the “centre of attention”. Active participants are rendered opaque and in the foreground to emphasise their visual presence, while other less-active participants appear slightly faded in the background in a manner that maintains awareness of their state without drawing undue attention. The system smoothly transitions the layering and appearance of the participants as their interactions continue. Every participant sees exactly the same composition, enhancing the sense of inhabiting a “shared space”.
Whether the visual feedback image is displayed in a separate portion of the display as is the case of the “Three” and NetMeeting systems, or as an integrated composite image as is the case in the Reflexions system, a common requirement is that the screen be large enough to display both images simultaneously without significant overlap. In cases where the screen is not large enough to display both images in their entirety, the visual feedback portion of the display may partially occlude the remote display portion of the display, as is common with the “Three” system. Where the screen is usually large enough to display both images, the images are usually depicted side-by-side or one on top of the other without significant overlap of the images of the users, as is the case with the NetMeeting and Reflexions systems. This may present further disadvantages in that the arrangement requires that the user attention in terms of eye gaze and/or head orientation be deliberately shifted from the visual feedback image to the remote image and vice versa, and especially where there is some distance between the two images.